Switching device



Sept-12,1944 c.v. PARKER 2,358,095

SWITCHING DEVICE Filed March 9, 1943 3 Sheets-Sheet l j lN'VENTOR I;CZMPAR/(ER ATTORNEY Sept. 12, 1944. c. v. PARKER SWITCHING DEVICE FiledMarch 9, 1943 3 Sheets-Sheet 2 //v VISA/TOR c MPAR/(E/P Tatented Sept.12, 1944 UNITED STATES PATENT OFFICE SWITCHING DEVICE Application March9, 1943, Serial No. 478,498

8 Claims.

This invention relates to switching devices and particularly toautomatic switches used in communication systems.

An object of the invention is to effect econom in the operation ofautomatic switches by reducing the electrical energy consumed while theswitches are in their actuated condition.

Another object is to obtain a greater latitude :in choosing the order orsequence of the functions performed in the operation of automaticswitches.

Other objects are to effect improvements in the selection and operationof off-normal switch -:contacts and in other respects to obtain improve-:ments in the structural design and operation of :automatic switches.

In the conventional crossbar switch now in use in automatic telephonesystems the method employed for the selection and operation of a set ofcontacts consists in first positioning a select bar individual to a rowof contact sets in one coordinate direction, then operating a hold barindividual to a row of contact sets in the other coordinate direction toeffect the closure of the desired set of contacts at the intersection ofthe operated bars, and finally releasing the select bar, the selectedcontacts being maintained in their closed condition by the continuedoperation of the hold bar. The subsequent release of the hold barrestores the operated contacts to normal. Switches of this type entailthe expenditure of substantial amounts of energy since the hold magnetsmust be maintained in an operated condition as long as the selectedcontact sets are closed. To obviate this energy consumption during theholding time of the switch, mechanical latching devices have beenproposed in the past for locking an operated set of contacts in theirclosed condition in order that both the select and hold magnets may bereleased. These latching devices, however, are objectionable in thatthey complicate the switch construction and increase the cost ofmanufacture.

In accordance with the present invention the disadvantages abovementioned are overcome by a crossbar switch structure in which each oneof the hold bars is effective in its restored position, where it isnormally held by a retractile spring, to close any one of the contactsets in the corresponding row, provided the appropriate select bar hasbeen moved to its selecting position. The hold magnet, therefore, doesnot actuate the selected set of contacts as in the conventional switch;its purpose is to move the hold bar momentarily to its off-normalposition while a select ill bar is operated to move the select finger orsimilar device into operative relation with respect to the selected setof contacts. Thereupon the hold magnet is released, and the hold barreturns to its normal position and in $0 doing operates and holds theselected set of contacts. Thus it is possible to select and close anydesired set of contacts in the switch by the momentary operation of thecorresponding select and hold magnets, and the selected set of contactsare maintained in their closed condition as long as desired withoutconsuming any electrical energy. To release a closed set of contacts itis merely necessary to energize momentarily the associated hold magnet.

A feature of the invention is a crossbar switch in which the conjointoperation of a select bar and a hold bar effects the actuation of thedesired set of contacts and in which said bars may be operated insequence, either one following the other, or simultaneously.

Another feature of the invention is a crossbar switch of the characterabove described in which individual sets of off-normal contacts areprovided for the respective hold bars. These offnormal contacts areselected and operated by means of an off-normal select bar whichcooperates with the hold bars in the same manner as the other selectbars of the switch.

These and other features of the invention will be described more fullyin the following detailed specification.

In the drawings accompanying the specification:

Fig. l is a front view of a crossbar switch in which the features ofthis invention are incorporated;

Fig. 2 is a perspective view showing the operating mechanism at one ofthe cross-points of the switch;

Fig. 3 is a detail view looking down on the contact operating mechanismand showing the hold bar and the select finger in their normalpositions;

Fig. 4 is a similar view but showing the hold bar in its off-normal orattracted position and the select finger in readiness for movement intoone of its selecting positions;

Fig. 5 illustrates the positions occupied by the select finger and holdbar while they are holding a set of contacts in closed position;

Figs. 6, 7 and 8 are side views showing the selecting and operatingmechanism in different stages of operation;

Fig. 9 is a view of the selecting and operating particular switch butmay be applied to switches of all types in which it may be found useful.

Referring now to the drawings, first to Fig, 1, the crossbar switchherein disclosed includes a frame comprising the upper and lower channelmembers I and 2 and the end plates 3 and 4, which interconnect themembers i and 2 and'are welded or otherwise joined thereto.

The frame thus formed supports a series of vertical units 5, 6, 1(usually ten or twenty in number). Each of these includes a mountingplate 8, which'suppo'rts the several sets of contact springs forming theassociated vertical row and also supports the associated operating andholdingbar 9. The mounting plates isdetachably secured to theupper andlower frame members l and 2 by means of screws in and H, its fixedposition in the frame being determined by its engagement with the slotsl2 and 13. The stationary vertical contact strips [4 extend the fulldepth of the vertical row 5, and the individual sets of movablespring-contacts at the successive cross-points in the row are arrangedto engage thesestationary contact strips when selected and operatedbythe switch mechanism. Usually there are ten of these movable sets'ofspring contacts in.each.vertical row, and the ten horizontal rows formedby these movable contact sets .may be multipled, if desired, .andconnected to ten respective external circuits. The hold bar 9 ispivotally supported on the. forward edge of the mountingplatefiwith itsarmature I5 in operative relation to the-associated hold magnet 16, anda retractile spring, which will .be explained hereinafter,servesonormally to hold the bar 9 in s c t c -o era in position. .Inasimil m ner the remaining. yertical units ,5, 1 ,include ti plate .8,Wh hs pport th c permine. Q Q Q l l SU-WS nd m vab ta t p ngs andtheresp cti e ho dbar i9. .26.

The horizontal or select bars are arranged as hcw in Fi Us all erearefive of these bars 2|, 22, 23, 24, (one being omitted in the draw n ea hbar er n two h riz ta ro of contacts. For example, the bar 2| may beoperated in one direction by magnet to rotate the e c fin e into opeativ e atio with respect tothe contact sets of one horizontal row andmay be rotated in the other direction by magn 26 to po i n. heselectfingelf in operative relation with the contact sets of theadjacent horizontal row.

The five select bars 2!, 22, 23, 24 are provided with individualsets ofelf-normal spring contacts 21, 28, 29, 30, etc. Each time the barzl, forexample, is rotated in onedirection it closes the off-normal contactsprings 21, and each time the bar rotates in the other direction itcloses the ofi-normal contact springs 23.

The switch is also equipped with off-normal spring contact sets 3 3 2,33, which are individual respectively to the hold bars 9, i9, 28. Aswill be explained hereinafter thesehold bar off-normal contact sets areclosed by the conjoint operathe cooperating select and hold magnets havebeen deenergized and is further capable of releasing an operated set ofcontacts in response to the simple act of energizing the hold magnetmomentarily. To this end each hold bar, such as the hold bar 9 (shownmore clearly in Figs. 2

to 9) is provided with a retractile spring 35 which normally holds thebar and with it the operating plate 36 in the contact-closing position.The plate 36 is fixed -to the hold bar 9 in parallel therewith as shownin Fig. 2, andthe force of the spring 35 rotates the plate 36 and holdbar 9 as a unit about the vertical mounting plate fl as a fulcrum. Inthis normal position the operating plate 36 engages and fiexes t hetenselect fingers 37 of the associated vertical row. With the bars 2 land 9 in their normal positions, each one of these fingers, such as thefinger 3! shown in Fig. 2, is flexed by the plate 36 and lies in acentral position between the contactoperating springs 38 and 39 withoutengaging either one of them. The contact-operating springs 38 and 39are-bent .to form recesses (illustratedniore clearly in Fig. 3) intowhich the plate 36 enters without disturbing said springs. Each of thecontact-operating springs 33 and 39 carries an insulating stud 40 whichserves, when the contact-operating spring is moved by the hold bar asexplained hereinafter, to fiex the movable contact springs 4| of theassociated set into engagement with the respective stationary-contactstrips 42.

The springs 38 and 39 are alsoformed with integral guide portions .43and 44. The purpose of these guides .43 and 44 is to-enable theoperation of the select and hold bars in either sequence. If, forexample, the select bar 2| is rotated by magnet 25 while the hold bar 9is in its normal retracted position, the select finger 31 moves upagainst the horizontal surface of the guide 43. Subsequently when magnet['6 is energized to rotate the bar9, .the, operating plate 35 iswithdrawn from the recesses in the springs 38 and 39; and the finger 31,being released, moves along the surface of the guide 43 until it escapesand advances, by reason of its own tension, into the selecting positionopposite the uppermost spring 38, as seen in Fig. 8 Similarly, if-theselect bar 2| is rotated in the opposite direction by magnet 26, thefinger 3.! engages the guide 44 and moves along the surface of thisguide, when the hold bar is subsequently withdrawn, until it escapes andassumes the selecting position opposite the lower contact-operatingspring 39. On the other hand, if the hold magnetlfi is operated beforethe select magnet, the withdrawal of the operating plate 36 permits theflexed spring 31 to move freely in the horizontal plane midway betweenthe guides 43 and 44 until it reaches the position shown in Fig. 4.Thereafter. the operation of the select bar 2| causes the finger toassume a selecting positionopposite either theupper Spring 38 or thelower spring 35, depending upon the direction of rotation of the selectbar. Finally, the release of the operated hold magnet l6 permits theretractile spring 35 to restore the hold bar 9 and the operating plate36 to normal. The operating plate 36 in returning to normal flexes thepositioned select finger 31 against either the spring 38 or the spring39, depending upon the selection made, and urges the contact-operatingspring into the contact-closing position. This position of the mechanismis clearly shown in Fig. 5.

The side view of Fig. 6 shows the mechanism in its normal position,corresponding to Figs. 2 and 3. The select bar 2| is in its normalposition holding the select finger 31 midway between thecontact-operating springs 38 and 39, and the hold bar 9 is rotated bythe retractile spring 35 to its normal position in which the operatingplate 36 flexes the resilient finger 31 between the guides 43 and 44 butwithout touching either of them.

The side view in Fig. 7 illustrates the mechanism with the select bar 2|in its rotated position and with the hold bar 9 at normal. The rotationof the bar 2| urges the select finger 31 up against the surface of theguide 43 on the operating spring 38. If now the hold magnet I6 isenergized to rotate the bar 9 to its operated position, the withdrawalof the operating plate 36 permits the finger 31 to slide along thesurface of the guide 43 until it escapes from the guide whereupon itsflexure causes it to move up into the position illustrated in Figs. 8and 9. In this select position the spring finger 3! lies opposite asmall notch 45 in the plate 35. When the hold bar is subsequentlyreleased and restored by the spring 35 to its normal position, the notch45 traps the finger 31 and moves it and the operating spring 38 into thepositionshown in Fig. where the contact springs 4| and 42 of theassociated set are closed.

In a similar manner the rotation of the select bar 2| in the oppositedirection causes the positioning of the finger 31 in line with the notch46 and opposite the lower contact-operating spring 39. With the springfinger in this position the release of the hold magnet and therestoration of the hold bar causes the closure of the lower set ofcontact springs of the cross-point.

As hereinbefore described, the off-normal contact springs individual tothe respective hold bars are selectively operated under the jointcontrol of the associated hold bar and the special offnormal select bar34. The bar 34 is rotated by a select magnet 41 in a direction toposition the resilient select fingers opposite the contactoperatingsprings associated with the off-normal contact sets. In the normalcondition of the switch the retracted hold bars 9, I9, 20 flex thespring fingers on the select bar 34 to a position under but not incontact with the guiding surfaces of the respective contact-operatingsprings 48, 49, 50. When the hold bar is rotated for the purpose ofestablishing a connection through one of the switching contact sets, thecorresponding spring finger on the off-normal bar 34 is unflexed andreleased to a position with respect to the contact-operating springwhich corresponds to the position of the finger 31 illustrated in Fig.4. Thereafter the rotation of the off-normal bar 34 tilts the springfinger to a position opposite the spring 48, whereupon the restorationof the operated hold bar closes the off-normal set of contact springs 3|associated with that hold bar. With this arrangement it will be seenthat the off-normal contact springs associated with a hold bar may beoperated each time a set of switching contacts in the correspondingvertical row is operated by arranging the circuits such that theoff-normal select magnet 41 is energized simultaneously with theenergization of the particular select magnet that is required forselecting the desired set of switching contacts.

' These off-normal contact springs, associated with the vertical or holdbars of the switch, are sometimes required for circuit reasons. Forexample, when the switch is used as a line switch, the oiT-normalcontact springs may serve as the cut-off contacts for the subscribersline. In the conventional cross-bar switch these springs may be operateddirectly from the hold bar, which is moved to its operated position andmaintained in such position throughout the connection. In the switchdisclosed herein, however, the hold bars are normally in theircontact-actuating position and also occupy this same position during thecontact closure periods. Therefore, the direct movement of the hold barcannot be utilized to close and maintain closed the associatedoff-normal contact set. While it would be possible to secure theequivalent of an off-normal contact set at each cross-point, this wouldincrease the size and cost of the switch and would be impractical inother respects. Such an expedient is avoided in the switch disclosedherein by providing the ofli normal bar above described for operatingthe off-normal contact set whenever one of the associated sets ofswitching contacts is operated.

To review the operation of the switch as a Whole, assume now that it isdesired to establish a connection through the upper set of contacts 4|lying at the intersection represented by the select bar 2| and hold bar9. When contacts 4| are closed, it is desirable to close the off-normalset of contacts 3| and to maintain the oil-normal contacts in a closedcondition until the contacts 4| are again opened. Since the contact set4| is controlled jointly by the select magnet 25 and the hold magnet I6,it is necessary that both of these magnets be energized concurrently fora brief interval of time. The order in which they are energized may bechosen to suit the particular circuits with which the switch is used.That is to say, the select magnet 25 may be energized followed by theenergization of magnet H5, or magnet |6 may be energized first followedby the energization of magnet 25. Moreover, since the off-normal contactset 3| depends on the joint control of select magnet 41 and hold magnetl6, the magnet 41 should also be energized during some portion of theperiod in which the magnet I6 is energized.

While the operating circuits of the switch are subject to manyvariations, Fig. 10 illustrates one manner in which the magnets may beenergized for operating the switch contacts. At the proper time in theoperation of the system energizing circuits are closed for the controlrelays 52 and 53. Relay 52 closes a circuit from battery through itscontact, winding of select magnet 25 and winding of off-normal selectmagnet 41 to ground. Relay 53 closes an obvious circuit for the holdmagnet l6. Magnet 25 rotates the bar 2| to move the select finger 31upwardly. Magnet |6 rotates the hold bar 9 against the tension of spring35 to release the finger 31 from its normal position between theoperating springs 38 and 39, permitting the finger to assume its selectposition opposite the upper contact-operating spring 38 as best seen inFig. 8. Magnet 41 rotates the. bar 34 to, move the select: finger 54'Iupwardly, and the rotation of the hold bar 9. also releases this fingerfrom. its normal flexedposition and permits it to. assume. its operativeposition opposite the contact-operating spring 48; (see Fig. 1).,

The select fingers 31. and; 54 are now in, their operated positions, andthe next step is: to apply a force to each one of these fin ers for clsin the, associated set of contacts. This is accomplished by thedeenergization 015 th 1. ..Qldmagnet l6 while the select magnets 25 and41 are being; maintained in an energized, condition. Upon thedeenergization of magnet- N the retractile spring; 35 restores the holdbar 9 to itsnormal position and in so doing" rotates the operating plate36 against the, positioned fingers 3:1 and 54, forcing these fingersagainst contact-operating springs 38 and 48 and in turn. forcing thesesprings to a, position where they close the associated set of contacts4| and 3|. The circuits of; magnets and 47 may now be opened to permitthe deenergization of these magnets and the restoration of theassociated bars 2| and 34 to. their normal positions. Although the bar21- restores to its normal position the finger 3;! is held in its con-.tact-closing position; by the force of; the, spring on the operatingplate 36. The notch in the plate 36 serves to hold the finger 31' inits;

trapped position and prevents it from restoring when the bar 2l isreturned to its normal posi-.

tion. In a similar manner the select finger 54 is.

tive operation of a desired setof switchcontacts m y a so. e. aooomr niyp r ti n of ncrmal contacts by; the additional energizationof a selectmagnet concurrent with the operation of the switching contacts. The factthat all op-. erating magnets are in a deenergized condition during theholding; time of the. con ection is-very important; it reduces to agreat extent the. cu;r-.

rent consumption required for; the operation of the switch magnets. Whenthe connection is no longer r q i ed. h set of. ont cts; a d t e.off-normalsetSi may be released by the simple act of energizing the holdmagnet 16. 0. 3 abljicf interval. The energization of this -n 1agnet11o,- tates thehold bar 9, which releases the fingers and. 5 a d rmihem. to es o e hei po t on r es ndin o. the. nor a p sitions: o the s et ars i and 34;. Upon the. s b

quent. re ase o m n t the ars. etur s to its. or alno tion. a d, o d nfle es; the; n ers 3? and h iz nta ly but wit utafi te ing theassociated contact springs.v

It Will be understood, of course, thatthe switch disclosed herein, likethe usual; crossbar switch, is capable of establishinga plurality ofconcurrent connections throughits cross-point contacts.

flexibility of; the, contact select fingers per-s...

mits a, select bar to be operated-and; released 1:e-. peatedly without.disturbing a connection that is being held by; one of; the.fleniblefingers. on said. bar. Similarly: the; ofienormal; select bar3.4 may be. operated and released; any. desiredv number of times whilone or more; of the ofi-norinal con-J tact sets. are. in their closedcondition. Since they offenormal, select magnet 4.! is common to, theother select. magnets of the switch, it is. convene ient to. operatethis magnet, as illustrated in Fig, 1,0, in series. with any one of theselect magnets: that may be chosen for operation.

What is claimed: is: l

1.. The combination in a crossbar switch of a plurality of sets ofseparately-operable contacts, a select. bar having a. plurality ofselect. elements thereon, one. for each set of contacts, said select barin its normal position serving to hold said Select; elements out ofoperative relation with the contact sets, a hold bar having a normalposition and an. actuated position, a magnet for said hold bar servingwhen energized to. move the bar from normal to its. actuated position,means for actuating said select. bar to. position said select elementsin operative relation to said contact sets while said hold bar is in itsactuated position, and means acting on said hold bar to restore it to;its normal position upon the deenergization of said magnet, said holdbar in its restoring move ment acting; upon one of said positionedselect ele.-. ments to operate the corresponding sets of con-. tacts,and to maintain them in an operated con-.. dition.

2, The combination in a crossbar switch or" a plurality of sets of:separately-operable contacts, a select bar having a plurality of selectfingers thereon, one ior each set of contacts, said select. bar itsnormal position serving to hold said select fingers out of operativerelation with said contact sets, a hold bar having a normal position a dan. u ted. positi n, a hold magnet serving when energized to nQve saidhold her from its normal to t t at d. p it on. a e e t ma net o t in a dse ec bar to position said so.- lect fingers in operative relation tosaid contact sets while said hold bar is in its actuated posit-ion, anda c a tile s r cting on aid. hold bar t stor t o i normal position uponthe de-. one si on o i hold ma net said. ho d bar n its e tor n m veent. ac in up one f saidpositioned select fingers to operate thecorresponding set of contacts and to maintain them in an operatedconditon after said select magnet is deenergized,

3, Thcc b on i a r ss r s i ch o a plurality of se o s pa ate y-ope b econ ac s. a. select bar havinga plurality of select elements thereon,one for each set of contacts, said eiements being movable in onedirection to a select. position and in a second direction to an operateposition, a hold bar having a normal position and an actuated position,said hold bar in its. normal; position serving to hold a particular oneof said select elements actuated in the operate di ec on. a gn t f mo is sa d hold bar from its normal to its actuated position to re leasesaid particular element in the operate direction, means for actuatingsaid select bar to mgve said particular element to the select positionwhile said hold bar is in its actuated po-v sit-ion, and means acting onsaid hold bar to. 13* store it to its normal pQsition upon thedeenergi-zation of said magnet, said hold bar in its restoring movementserving to reoperate said particular select element in the operatedirection to operate the corresponding set of contacts and to maintainthem in an operated position.

4 The combination in a crossbar switch of a p u a ty of s ts of seply-operable contacts. a elec bar hav n pl ral ty of; flexible. sel ct.

fingers thereon, one for each set of contacts, said fingers beingmovable in a selecting direction for the purpose of selecting theassociated sets of contacts and flexible in an operate direction for thepurpose of operating the selected sets of contacts, a hold bar having anormal position and an actuated position, said hold bar in its normalposition serving to hold a plurality of said fingers flexed in theoperate direction, a magnet for operating said hold bar from its normalto its actuated position to release the flexed fingers in the operatedirection, means for actuating said select bar to move a particular oneof the fingers released by said hold bar into the selecting positionwith respect to the associated set of contacts, and means acting on saidhold bar to restore it to its normal position upon the deenergization ofsaid magnet, said hold bar in its restoring movement acting upon saidparticular select finger to reflex it in the operate direction for thepurpose of operating the associated set of contacts.

5. The combination in a crossbar switch of a plurality of sets ofseparately-operable contacts, a plurality of select bars individualrespectively to coordinate rows of contact sets in one direc-,

tion, each bar having a plurality of select fingers thereon, one foreach set of contacts in the associated row, each select bar in itsnormal position serving to hold its select fingers out of operativerelation with the contact sets, a plurality of hold bars individualrespectively to rows of contact sets in the other coordinate direction,each hold bar having a normal position and an actuated position, eachhold bar having an individual magnet serving when energized to move thebar from its normal to its actuated position, means for actuating anyone of said select bars to position its select fingers in operativerelation to the associated contact sets while any one of said hold barsis in its actuated position, and means acting on the actuated hold barto restore it to its normal position upon the deenergization of theassociated magnet, said hold bar in its restoring movement acting uponone of the positioned select fingers of said operated select bar tooperate the corresponding set of contacts and to maintain them in anoperated condition following the release of said select bar.

6. The combination in a crossbar switch of a plurality of sets ofswitching contacts, select bars individual respectively to rows ofcontact sets in one direction, hold bars individual respectively to rowsof contact sets in another direction, of!- normal contact setsindividual respectively to said hold bars, an off-normal bar common toall of said hold bars, an individual select magnet for moving each ofsaid select bars to select the contact sets in the associated row, amagnet for said off-normal bar, means for operating the magnet for saidoff-normal bar each time any one of said select magnets is operated, andmeans for actuating any one of said hold bars while any select bar isoperated and while said off-normal bar is operated to selectivelyoperate the associated set of switching contacts and the associated setof oil-normal contacts.

7. The combination in a crossbar switch of a plurality of sets ofswitching contacts, first operating bars individual respectively to rowsof contact sets in one direction, second operating I bars individualrespectively to rows of contact sets in another direction, ofi-normalcontact sets associated respectively with said second bars, anoff-normalbar common to said off-normal contact sets, means foractuating any one of said first operating bars, means for actuating saidoff-normal bar, and means for actuating any one of said second operatingbars, the actuated second bar serving to cooperate with the first barand with the off-normal bar while in their actuated positions to close adesired set of said switching contacts and a desired set of off-normalcontacts.

8. The combination in a crossbar switch of a plurality of sets ofseparately-operable contacts, select bars, each having a plurality ofselect elements thereon, said select elements bing individualrespectively to said sets of contacts, said select bars in their normalpositions serving to hold said select elements out of operative rela--tion with the contact sets, a hold bar having a normal position and anactuated position, magnets individual to said select bars and a magnetfor said hold bar for moving a select bar and said hold bar eithersimultaneously or successively in either sequence to their select andactuated positions respectively to position the corresponding selectelement in operative relation to the associated contact set, and meansacting on said hold bar to restore it to its normal position, said holdbar in its restoring movement acting upon the positioned select elementto operate the corresponding set of contacts and to maintain them in anoperated condition.

CARLYLE V. PARKER.

